Yep, you'll regret the 5 on the front and trying to split the screen. I understand the $ thing though. If ya really want to get squirrely and only rely on the FF for depth, then get the 5, run it full on GPS and mount an elcheapo FF next to it. In effect, you'll have a larger GPS output size than splitting a 7 or 8 and still have the ability to switch to color 2D (when you really need it) or SI if you're going the LSS1 route.

Past that, you can look for a discontinued used LCX in 7".

Wannabe...